Introduction to Longfeng Valley Sulfur Valley Recreation Area: Longfeng Valley and Sulfur Valley are both located on the southwest side of Yangmingshan National Park, close to Xinbeitou and Tianmu areas. The old name is "Dashuangzui", which is the site of sulfur mining in the Yuyong River in 1697. There are rich volcaniclastic and sedimentary rock geological terrains and cultural landscapes.